Cast "Amphitheater"

[Fishman]

At ~7:40 in the video below he talks about the angle of this casting and building an "amphitheater" with the different zones... Has something like this been tested, or is it just anecdotal observation and justification for the shape?

https://www.youtube.com/watch?v=yM6FSu1LjCY

[Fishman]

Just bumping this up again for any thoughts and comments on focusing the radiational heating zones.